This invention relates to ophthalmic surgeries performed on the eye. The invention relates specifically to such surgeries where an increased pressure is developed inside the eye enclosure. Such surgeries include, for example and without limitation, cataract surgery, vitrectomy, glaucoma procedures, and other procedures undertaken behind the iris.
During such surgeries, one or more surgical openings are created in the anterior portion of the eye for the purpose of inserting, into the eye, various surgical instruments, as well as fluids and other assisting items which are used in the surgical procedure or which are temporarily inserted into the eye during the procedure, or which are inserted for the purpose of leaving such item in the eye as part of the surgical procedure. Such surgical openings are commonly created adjacent, and anterior of, the iris, generally adjacent the outer perimeter of the iris, optionally in the sclera.
During such surgical procedures, it is common to add one or more fluids to the anterior chamber of the eye, and it is common that at least some of such added fluid is positioned behind the iris. The addition of such fluid can cause an increase in the fluid pressure inside the eye.
For example, during cataract surgery, one or more surgical openings may be made adjacent the outer perimeter of, and in front of, the iris. One or more instruments are inserted through the surgical openings, in front of the iris, and manipulated inside the anterior chamber, along with administration of suitable fluids inside the anterior chamber, in removing the original natural lens, and inserting a replacement intraocular lens in its place.
In the alternative, during the surgery, the patient may tense the eyelids, which also raises the pressure inside the eye.
Elements of the iris tissue are relatively thin, and are loosely connected to each other. The iris, as a whole is quite mobile. Accordingly, the iris responds to any such increase in pressure by moving away from the area of relatively greater pressure toward an area of relatively lower pressure.
In addition, the strength of the iris tissue can vary from patient to patient, depending on a number of health-related factors, and/or life style factors, including any drugs, such as sympathetic blockers, which the patient may be using.
Thus, as the pressure inside the anterior chamber increases during the surgical procedure, there is a tendency for the iris is to move away from the increased pressure toward an area of relatively lower pressure. The ambient atmosphere outside the eye is such an area of lower pressure. The surgical opening(s) are made through relatively soft and extensible tissue. Any area of the surgical opening which is not fully occupied by an instrument or other article, or to the extent the surgical opening can be enlarged slightly by the internal pressure inside the anterior chamber, such as by stretching the tissue surrounding the surgical opening, provides a path for the iris tissue to move toward that area of lower pressure outside the eye. Any such movement of the iris tissue outside its normal zone of movement creates abnormal stresses on the iris tissue, and can be damaging to the iris tissue.
The result of such abnormal movement of the iris tissue is the protrusion of iris tissue, commonly referred to as prolapse, through the surgical opening. Such prolapse of iris tissue through the surgical opening creates abnormal stresses in the iris tissue and can, in some cases, result in tearing of the iris tissue.
FIG. 1 shows an example of a generally healthy human eye 2 before a surgical procedure has been initiated. There are no openings in the outer tissue adjacent the anterior chamber. There is no path for prolapse of the iris through the eye enclosure.
FIG. 2 shows the same eye as in FIG. 1, but illustrating such prolapse. FIG. 2 illustrates a surgical opening 3 created through the cornea 4 or sclera 5 adjacent the outer edge of the iris 6. As a result of increased pressure inside the anterior chamber, for example during such surgical procedure, the iris has begun to prolapse through the surgical opening and thus a prolapsed portion 8 of the iris extends outside the eye.
It is desirable to prevent such prolapse, which can damage and/or tear the iris tissue and, even where the prolapsed tissue can be drawn back inside the eye enclosure through the surgical opening, such trauma to the eye can result in the patient experiencing pain during the surgery and the patient may experience excessive glare post-surgery.
Thus, the problem to be solved by the invention is to address such prolapse, either by preventing the occurrence of such prolapse, or by providing remedial measures to reverse such prolapse after the prolapse occurs such that the iris tissue moves back inside the eye enclosure.
A conventional treatment for iris prolapse is to watch for prolapse, and to react to such prolapse when prolapse is observed during the surgical procedure. The conventional reaction to prolapse, once the prolapse is observed, is to maintain the increased pressure in the anterior chamber behind the iris, and to increase the pressure inside the anterior chamber in front of the ins. Such increase in pressure in front of the iris apparently urges the iris tissue which remains inside the eye envelope to move rearwardly inside the eye enclosure, thus drawing the prolapsed tissue back through the surgical opening and inside the eye.
Another conventional treatment is to depress the iris and the intraoptical lens inside the eye when the iris prolapses.
Still another conventional treatment is to place a viscoelastic plug in any surgical opening which is not needed immediately, for the period when the pressure is to be increased in the anterior chamber, and then to remove the viscoelastic plug as part of completing the surgical procedure.
Any tissue which may have been torn in the process of a prolapse may be permanently lost. In addition, any iris tissue which has been exposed to ambient atmosphere in the meantime, has also been exposed to any contaminants in the atmosphere, including any pathogenic bacteria, viruses, and the like with which the prolapsed tissue may have come into contact in the atmosphere. So allowing the prolapse to occur, and then responding to such occurrence, entails additional risk of contamination and/or tissue tearing, including the risk of corresponding complications developing as a result of the surgery.
Thus it would be desirable to provide a proactive method for preventing the occurrence of iris prolapse.
It would further be desirable to prevent the iris tissue from becoming exposed to the ambient environment outside the eye enclosure.
It would be further desirable to, as much as possible, prevent the stress and potential for tearing of iris tissue as a result of increased pressure inside the eye enclosure while performing ophthalmic surgery.
It would be desirable that the device would catch the pupil (inner) edge of the iris and maintain dilation of the pupil allowing for the duration of surgery, thereby assisting visualization of the deeper contents (lens) during surgery.
It would further be desirable to avoid inserting small temporary plugs into the surgical opening, lest such small items become fragmented, or lest such small items be inadvertently left inside the anterior chamber at the end of the surgery.
These and other needs are alleviated, or at least attenuated, by the novel products, systems, and methods, of the invention.